Nanocellulose nanocomposite hydrogels: technological and environmental issues

Over the last decade, nanocellulose-based nanocomposite hydrogels have emerged as promising materials in different fields of application such as medicine, food, and agriculture. The present review addresses the advances in the synthesis methods and technological applications of these hydrogels. Different chemical and physical cross-linking methods used for the design of cellulose nanocrystals, cellulose nanofibrils, and bacterial cellulose hydrogels are discussed in detail. Nanocomposite hydrogels based on nanocellulose or reinforced with nanocellulose have good mechanical properties, biocompatibility, and biodegradability and allow the incorporation of several molecules or solutes, which can provide a slow and controlled release profile. The major advances exploring these hydrogels in biomedicine, food, and agriculture are reviewed. Finally, challenges and environmental issues related to their production are briefly discussed.